package cn.kevenpotter.leetcode.easy.e13;

public class RomanToInt {

    public static void main(String[] args) {
        System.out.println(romanToInt("MCMXCIV"));
    }

    public static int romanToInt(String s) {
        int sum = 0;
        int preNum = getValue(s.charAt(0));
        for (int i = 1; i < s.length(); i++) {
            int num = getValue(s.charAt(i));
            if (preNum < num) sum -= preNum;
            else sum += preNum;
            preNum = num;
        }
        return preNum + sum;
    }

    public static int getValue(Character ch) {
        switch (ch) {
            case 'I':
                return 1;
            case 'V':
                return 5;
            case 'X':
                return 10;
            case 'L':
                return 50;
            case 'C':
                return 100;
            case 'D':
                return 500;
            case 'M':
                return 1000;
            default:
                return 0;
        }
    }
}
